4.3. Platelet Aggregometry Assay

Blood with 3.8% tri-sodium citrate (9:1 v/v) was centrifuged for 10 min at 140× g at room temperature to produce the platelet-rich plasma. The platelet-poor plasma was obtained by further centrifuging the remainder of the platelet-rich plasma specimen at 700× g for 20 min at room temperature. Platelet aggregation was determined on an optical aggregometer 490 Chrono-Log (USA) with a self-calibration system. 500 μL platelet-poor plasma was placed in an aggregometer comparison cuvette. Next, 500 μL of platelet-rich plasma was added to a cuvette of an aggregometer with a magnetic stirrer. Samples were incubated for 2 min at a temperature of 37 °C. Then, the aggregation inducer was added to the platelet-rich plasma cuvette and the level of aggregation was measured relative to the cuvette with platelet-poor plasma for 5–6 min. Collagen (2 μg/mL), ADP (5 μM), adrenaline (10 μM) and ARA (0.5 mM) were used as platelet aggregation inducers. Platelet aggregation was expressed as a percentage.